code: def alphanum(v):
      """Filters a string to only its alphanumeric characters."""
      return re.sub(r"\W+", "", v)
  
imports: import os
  import re
  import uuid
  from abc import ABC, abstractmethod
  from dataclasses import dataclass
  from pathlib import Path
  from typing import Optional, Union
  from ludwig.api_annotations import DeveloperAPI
  from ludwig.utils.fs_utils import checksum
  from ludwig.utils.types import DataFrame
label_desc: Use image node_id 1 for calling a global function with example usage: alphanum(v) and returns: re